01 -
Combine cold butter, flour, sugar, cinnamon, lemon zest, and salt. Pulse in a food processor until mixture resembles coarse crumbs.
02 -
Press two-thirds of the dough evenly into a parchment-lined rectangular baking pan to form the crust.
03 -
In a bowl, gently toss blackberries with sugar, lemon juice, and cornstarch until evenly coated.
04 -
Spread blackberry mixture evenly over the crust. Crumble remaining dough over the filling, leaving it loose for a crumbly texture.
05 -
Bake at 350°F (175°C) for 45-50 minutes until topping is light golden brown and filling is set but slightly jiggly.
06 -
Allow bars to cool completely before slicing to let the filling set. Refrigerate if needed to speed cooling.